clean customed gem.
mod11 hw1 finished, add admin for view and controller, and fix related AppMailers.delivery rspec test.
mod11 hw2 (1) done, handle and test :create request without file uploading.
mod11 hw2 (2) done, CarrierWave for cloud platform has not configured.
mod11 hw3 finished, added video_url feature in Model and View.
mod11 hw4 finished, added feature test for admin_add_new_video
Merge pull request #14 from jamesyang124/mod11

Mod11